Abstract: To investigate the changes of PSI and PeSI during heat acclimatization training and the relationship between them, heat acclimatization training in high-temperature environment was carried out by using a climate chamber. 16 healthy male college students were taken as testees, they were randomly assigned to test under different conditions consisting of different temperatures and labor intensity,and PSI and PeSI in subjects were calculated. The differences of PSI and PeSI before and after heat acclimatization training were analyzed by paired sample t-tests. The variance analysis method was used to analyze the influences of temperature and labor intensity on the PSI and PeSI. The relationship between PSI and PeSI was studied by correlation analysis and regression analysis. The results demonstrate that heat acclimatization training can reduce the PSI and PeSI of testees and the key factor influencing the PSI and PeSI is the labor intensity at the time of training, that PSI can be predicted by PeSI, but the prediction accuracy varies with the working condition, when the temperature is 36～38 ℃ and the relative humidity is 50%, the prediction accuracy of PSI under heavy labor intensity condition is greater than that obtained under the moderate intensity condition.

Key words: physiological strain index (PSI), perceptual strain index (PeSI), heat acclimatization, high-temperature environment, labor intensity